c# - Visual Studio 2015 (Community) designer shows NullReferenceException for blank Universal App

Question

I'm getting a bit frustrated by this, maybe someone has encountered a similar problem or has an idea how to fix it.

I upgraded to Windows 10.
I installed Visual Studio 2015 Community.
I created a new solution, with only 1 project for a blank Universal Windows app. I am using C#.

Problem: I tried to open MainPage.xaml in the designer, but the designer won't load. I get a NullReferenceException in the designer window. I tried opening it in Blend, same result. As Visual Studio suggested, I tried turning off the "Run project code in XAML Designer" feature in the Options menu, but it didn't help.

It has no problem with opening other xaml files in the designer though (WPF, Windows Phone 8, or 8.1 Universal apps all work fine). The app runs both in on local machine, and in emulator, it is only the designer that's acting up.

Any suggestions are welcome.

EDIT

Exception from the designer window:

System.NullReferenceException
Object reference not set to an instance of an object.
   at Microsoft.VisualStudio.DesignTools.Platform.Metadata.MetadataStore.GetTypeConverter(Type type)
   at Microsoft.VisualStudio.DesignTools.WindowsXamlDesigner.WindowsUIXamlDesignTimeProperties.ResolveImplementation(IPlatformMetadata platformMetadata, DesignTimePropertyId neutralProperty, IType declaringType, PropertyChangedCallback callback)
   at Microsoft.VisualStudio.DesignTools.WindowsXamlDesigner.WindowsUIXamlDesignTimeProperties.RegisterProperty(IPropertyId neutralPropertyKey, IType declaringType, PropertyChangedCallback callback)
   at Microsoft.VisualStudio.DesignTools.WindowsXamlDesigner.WindowsUIXamlCommonDesignTimeProperties.Initialize(WindowsUIXamlDesignTimeProperties designTimeProperties)
   at Microsoft.VisualStudio.DesignTools.WindowsXamlDesigner.WindowsUIXamlDesignTimeProperties..ctor(IPlatformTypes platformMetadata)
   at Microsoft.VisualStudio.DesignTools.UniversalXamlDesigner.UniversalXamlPlatformMetadata.CreateDesignTimeProperties()
   at Microsoft.VisualStudio.DesignTools.WindowsXamlDesigner.Metadata.WindowsUIXamlPlatformMetadata.Initialize()
   at Microsoft.VisualStudio.DesignTools.WindowsXamlDesigner.WindowsStoreXamlPlatform.Initialize()
   at Microsoft.VisualStudio.DesignTools.Platform.PlatformCreatorBase.CreatePlatform(IPlatformReferenceAssemblyResolver referenceAssemblyResolver)
   at Microsoft.VisualStudio.DesignTools.Designer.Project.ProjectContextManager.GetProjectContext(IHostProject project, IPlatform platform, Boolean create)
   at Microsoft.VisualStudio.DesignTools.Designer.Project.ProjectContextManager.GetSourceItemContext(IHostSourceItem sourceItem)
   at Microsoft.VisualStudio.DesignTools.Designer.DesignerService.CreateDesigner(IHostSourceItem item, IHostTextEditor editor, CancellationToken cancelToken)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.RemoteDesignerService.<>c__DisplayClass12_0.<Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.IRemoteDesignerService.CreateDesigner>b__0(CancellationToken cancelToken)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.RemoteDesignerService.<>c__DisplayClass6_0`1.<MarshalInWithCancellation>b__0()
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.Call.InvokeWorker()

System.NullReferenceException
Object reference not set to an instance of an object.

Server stack trace: 
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.WaitForCompletion(NestedCallContext nestedCallContext, BlockingCall call, WaitHandle timeoutSignal)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.MarshalInSynchronous(Action action, Int32 targetApartmentId, CancellationToken cancelToken, CallModality callModality, String methodName, String filePath, Int32 lineNumber)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.MarshalIn(Action action, Int32 targetApartmentId, CancellationToken cancelToken, CallSynchronizationMode syncMode, CallModality callModality, String methodName, String filePath, Int32 lineNumber)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.ThreadMarshaler.MarshalIn(IRemoteObject targetObject, Action action, CancellationToken cancelToken, CallSynchronizationMode syncMode, CallModality callModality, ApartmentState apartmentState, String memberName, String filePath, Int32 lineNumber)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.RemoteDesignerService.MarshalInWithCancellation[TResult](IRemoteCancellationToken remoteToken, Func`2 func, ApartmentState apartmentState)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.RemoteDesignerService.Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.IRemoteDesignerService.CreateDesigner(IRemoteHostProject remoteProject, IRemoteHostSourceItem remoteItem, IRemoteHostTextEditor remoteEditor, IRemoteCancellationToken remoteToken)
   at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Object[]& outArgs)
   at System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg)

Exception rethrown at [0]: 
   at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
   at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.IRemoteDesignerService.CreateDesigner(IRemoteHostProject remoteProject, IRemoteHostSourceItem remoteItem, IRemoteHostTextEditor remoteEditor, IRemoteCancellationToken cancelToken)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.LocalDesignerService.CreateDesignerImpl(IRemoteDesignerService ds, IHostSourceItem item, IHostTextEditor editor, RemoteCancellationToken remoteCancelToken)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.LocalDesignerService.<>c__DisplayClass14_0.<Microsoft.VisualStudio.DesignTools.DesignerContract.IDesignerService.CreateDesigner>b__0(IRemoteDesignerService ds, RemoteCancellationToken remoteToken)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.LocalDesignerService.<>c__DisplayClass5_0`1.<MarshalOutWithCancellation>b__0(IRemoteDesignerService ds)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.ThreadMarshaler.<>c__DisplayClass27_0`1.<MarshalOut>b__0()
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.Call.InvokeWorker()

System.NullReferenceException
Object reference not set to an instance of an object.
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.WaitForCompletion(NestedCallContext nestedCallContext, BlockingCall call, WaitHandle timeoutSignal)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.MarshalOutSynchronous(Action action, Int32 targetApartmentId, WaitHandle aborted, WaitHandle timeoutSignal, CancellationToken cancelToken, String methodName, String filePath, Int32 lineNumber)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.MarshalOut(Action action, Int32 targetApartmentId, WaitHandle aborted, CancellationToken cancelToken, CallSynchronizationMode syncMode, WaitHandle timeoutSignal, String methodName, String filePath, Int32 lineNumber)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.ThreadMarshaler.MarshalOut[TValue](RemoteHandle`1 targetObject, Action action, CancellationToken cancelToken, CallSynchronizationMode syncMode, ApartmentState apartmentState, String methodName, String filePath, Int32 lineNumber)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.ThreadMarshaler.MarshalOut[TValue](RemoteHandle`1 targetObject, Action`1 action, CancellationToken cancelToken, CallSynchronizationMode syncMode, ApartmentState apartmentState, String methodName, String filePath, Int32 lineNumber)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.LocalDesignerService.MarshalOutWithCancellation[TResult](CancellationToken cancelToken, Func`3 func, ApartmentState apartmentState)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.LocalDesignerService.Microsoft.VisualStudio.DesignTools.DesignerContract.IDesignerService.CreateDesigner(IHostSourceItem item, IHostTextEditor editor, CancellationToken cancelToken)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.IsolatedDesignerService.IsolatedDesignerView.CreateDesignerViewInfo(CancellationToken cancelToken)

Answer 1

If you're using HP, this worked for me:

delete the "Platform" environment variable in System->Advanced System Settings->Environment Variables ...

In my case it said =HPD